"""Model registry. VRAM tier drives default. User can override."""
from __future__ import annotations

from dataclasses import dataclass
from typing import Literal

Kind = Literal["image", "video"]


@dataclass(frozen=True)
class ModelSpec:
    id: str
    label: str
    repo: str
    kind: Kind
    min_vram_gb: float
    nsfw_capable: bool
    download_gb: float = 0.0
    notes: str = ""


IMAGE_MODELS: list[ModelSpec] = [
    ModelSpec(
        id="sdxl-turbo",
        label="SDXL Turbo (fast, low VRAM)",
        repo="stabilityai/sdxl-turbo",
        kind="image",
        min_vram_gb=4.0,
        nsfw_capable=False,
        download_gb=7.0,
        notes="1-4 step sampling. Censored base. Good for safe content on weak GPUs.",
    ),
    ModelSpec(
        id="pony-xl",
        label="Pony Diffusion XL v6 (NSFW, anime/realistic)",
        repo="AstraliteHeart/pony-diffusion-v6",
        kind="image",
        min_vram_gb=8.0,
        nsfw_capable=True,
        download_gb=7.0,
        notes="Use score_9, score_8_up tags. Strong NSFW capability.",
    ),
    ModelSpec(
        id="illustrious-xl",
        label="Illustrious XL v0.1 (NSFW, illustration)",
        repo="OnomaAIResearch/Illustrious-xl-early-release-v0",
        kind="image",
        min_vram_gb=10.0,
        nsfw_capable=True,
        download_gb=7.0,
        notes="High-detail anime/illustration. NSFW-capable.",
    ),
    ModelSpec(
        id="sdxl-base",
        label="SDXL Base 1.0 (versatile)",
        repo="stabilityai/stable-diffusion-xl-base-1.0",
        kind="image",
        min_vram_gb=8.0,
        nsfw_capable=False,
        download_gb=7.0,
        notes="General-purpose. Censored.",
    ),
    ModelSpec(
        id="flux-schnell",
        label="FLUX.1 Schnell (high quality, 12GB+)",
        repo="black-forest-labs/FLUX.1-schnell",
        kind="image",
        min_vram_gb=12.0,
        nsfw_capable=False,
        download_gb=24.0,
        notes="State-of-the-art prompt adherence. 4-step.",
    ),
]

VIDEO_MODELS: list[ModelSpec] = [
    ModelSpec(
        id="ltx-video",
        label="LTX-Video 0.9 (fast, 8GB+)",
        repo="Lightricks/LTX-Video",
        kind="video",
        min_vram_gb=8.0,
        nsfw_capable=True,
        download_gb=18.0,
        notes="2-5 second clips at 24fps. Fast generation.",
    ),
    ModelSpec(
        id="cogvideox-5b",
        label="CogVideoX 5B (12GB+)",
        repo="THUDM/CogVideoX-5b",
        kind="video",
        min_vram_gb=12.0,
        nsfw_capable=False,
        download_gb=20.0,
        notes="6 second clips. Good motion quality.",
    ),
    ModelSpec(
        id="wan-2-1",
        label="Wan 2.1 T2V 1.3B (16GB+)",
        repo="Wan-AI/Wan2.1-T2V-1.3B-Diffusers",
        kind="video",
        min_vram_gb=14.0,
        nsfw_capable=True,
        download_gb=16.0,
        notes="Top-tier open video model. Needs diffusers>=0.32.",
    ),
]


def default_for_tier(tier: str, kind: Kind) -> ModelSpec | None:
    pool = IMAGE_MODELS if kind == "image" else VIDEO_MODELS
    tier_min = {"cpu": 0.0, "low": 0.0, "mid": 8.0, "high": 10.0, "ultra": 12.0}
    target = tier_min.get(tier, 0.0)
    if tier == "cpu" and kind == "video":
        return None
    if tier in ("cpu", "low") and kind == "image":
        return next(m for m in pool if m.id == "sdxl-turbo")
    if tier == "mid" and kind == "image":
        return next(m for m in pool if m.id == "pony-xl")
    if tier == "high" and kind == "image":
        return next(m for m in pool if m.id == "illustrious-xl")
    if tier == "ultra" and kind == "image":
        return next(m for m in pool if m.id == "illustrious-xl")
    if tier in ("low",) and kind == "video":
        return None
    if tier == "mid" and kind == "video":
        return next(m for m in pool if m.id == "ltx-video")
    if tier == "high" and kind == "video":
        return next(m for m in pool if m.id == "ltx-video")
    if tier == "ultra" and kind == "video":
        return next(m for m in pool if m.id == "wan-2-1")
    return next((m for m in pool if m.min_vram_gb <= target), None)


def list_for_tier(tier: str, kind: Kind) -> list[ModelSpec]:
    pool = IMAGE_MODELS if kind == "image" else VIDEO_MODELS
    tier_max = {"cpu": 4.0, "low": 6.0, "mid": 10.0, "high": 14.0, "ultra": 1000.0}
    cap = tier_max.get(tier, 1000.0)
    out = [m for m in pool if m.min_vram_gb <= cap + 2.0]
    out.sort(key=lambda m: m.min_vram_gb)
    return out


def find(model_id: str) -> ModelSpec | None:
    for m in IMAGE_MODELS + VIDEO_MODELS:
        if m.id == model_id:
            return m
    return None


def is_cached(spec: ModelSpec) -> bool:
    """Best-effort: check if HF snapshot exists in our cache dir."""
    from pathlib import Path
    cache = Path(__file__).parent.parent / "models" / "diffusers"
    if not cache.exists():
        return False
    folder = "models--" + spec.repo.replace("/", "--")
    return (cache / folder).exists()


def label_with_meta(spec: ModelSpec) -> str:
    nsfw = " · NSFW✓" if spec.nsfw_capable else ""
    cached = " · cached" if is_cached(spec) else f" · {spec.download_gb:.0f}GB download"
    return f"{spec.label}{nsfw}{cached}"